In the manufacture of many interior automotive trim products, such as a door cover for a passenger supplemental inflatable restraint (PSIR) airbag system, glove and console compartment doors, door panels and instrument panels, and the like, a flexible skin or shell is placed in the cavity of the foam injection mold and a rigid insert backing panel is supported within the mold cavity above the skin to enclose and define a space for foam between the skin and backing panel. The backing panel is formed with a foam entry hole aligned with a pour hole of the upper mold part to provide an opening for the injection of foam precursors into the space whereupon they react and expand to fill the space and generate a foam core therein. In most applications, the spacing between the skin layer and the opposing interior surface of the backing panel is generally uniform resulting in a foam core that is of generally uniform density. However, in the region of the foam entry hole, there is no support to back up the foam during its expansion and as a consequence the foam in this region develops to a lower density than the immediate surrounding foam. This variation in density is particularly problematic in applications such as airbag doors which have a very thin cross section (on the order of 8 mm or less in thickness). In such instances, the relatively less dense foam in the region of the foam entry hole shows through on the outer class A surface of the skin as a depression or a soft spot that is more easily depressed than the surrounding areas of the airbag door.
It is current practice to form such foam entry holes by stamping out or molding a pair of adjacent semi-circular openings in the panel to provide a thin web or bridge between the openings that serves in some applications as a locking connection for the foam injection tool. Such construction is shown, for example, in U.S. Pat. No. 4,784,366, commonly owned by the assignee of the present invention. The foam in these open pour hole regions is less dense than that of the surrounding foam producing the sunken or soft spots mentioned above in the finished product.